The invention relates to a mixed water preparation device comprising an operating unit for inputting a nominal value, and an electronic controller unit that is acting via a mechanical adjusting element on a control line for preparing mixed water depending on a temperature sensor for detecting the actual value. The invention, furthermore, relates to a method, in connection with which a nominal value, which can be input and preset via an operating unit, is acting upon a control line by means of a mechanical adjusting element for preparing mixed water via an electronic controller unit depending on an actual value detected with the help of a temperature sensor.
Such an electronic preparation of mixed water is known from DE 40 26 110. This known device is a system for preparing mixed water that comprises cold and hot water inlets, as well as a mixed water drain, and a control valve that is arranged upstream of the mixing chamber. An electronic controller and a digitally operating controller and computer unit are associated with the control valve. The controller and computer unit cooperates with a program memory. The mixed water can be prepared either with the help of the preset values input via an operating unit, or based on the values specified in a control program filed in the program memory.
This development is particularly based on the problem of fitting existing mixed water batteries with an electronic controller at a later time. The drawback of this construction set for equipping an existing system at some later time is that this is an additional external device. This device can be used only in rare cases within the sphere of private applications because the space conditions in the area of bathrooms are confined. Furthermore, such a high-quality mixed water preparation system is associated with optical restrictions on account of an additional device that can be mounted only on plaster, which is usually perceived as being not very attractive, visually speaking. Mounting the additional device on the plaster is mandatory also for the reason that the idea and purpose of the known device is to be able to replace the program memory associated with the control valve when so required. The device necessarily has to be freely accessible for such an exchange.
Therefore, the invention is based on the problem of providing a device and a method for the electronic preparation of mixed water that avoids the drawbacks existing in the prior art and is suitable in the sphere of the private home and household.
The problem on which the invention is based is solved by a device according to claim 1, as well as by a method according to claim 8.
Owing to the fact that according to the independent claim, both the electronic controller and the mechanical setting element are arranged in one single, compact unit of the device, it is possible to install the entire electronic device for preparing mixed water under the plaster. In addition, the compact and closed type of construction of the device permits dispensing with long cable installations that are susceptible to trouble. Furthermore, the electronic controller is optimally coordinated with the mechanical setting element.
A further surprising advantage can be achieved in that the preparation of the mixed water is completely controlled exclusively by means of one single temperature sensor. The omission of a diverse sensor system requiring considerable expenditure eliminates error sources and, furthermore, reduces costs required otherwise. This reduced sensor system can be compensated by ingeniously processing the measured values.
In an advantageous embodiment of the invention, provision is made for a stepping motor serving as the setting element. This stepping motor acts on a two-way mixing valve. Such an arrangement offers the benefit that the pre-specified control value is translated directly and clearly by means of the described setting element. This constitutes a distinct improvement vis-a-vis the elements comprising an expanding substance or bimetallic disks of the type usually employed for the preparation of mixed water. The setting elements mentioned last operate depending on the temperature, so that the behavior of the controller may change depending on the adjusted temperature.
A highly accurate temperature control would therefore always require the setting element to be monitored accordingly. This, however, is feasible only with substantial expenditure because of the behavior of the setting elements of the type specified above, which is highly dependent on the material employed for such elements and on the temperature.
The electronic device for preparing mixed water is advantageously connected with an interface module for connecting to it diagnostic and/or programming devices. The interface module may be used either for error diagnosis and purposes of parameterization, or for storing the required control programs. Furthermore, the interface module may permit a remote control of the electronic preparation of mixed water by means of a conductive connection or with the help of an infrared or radio control system. The device installed under the plaster may be supported via the interface module as well.
By providing a display unit serving as the operating unit, which comprises a display monitor in addition to an input unit, it is possible to take into account the fact that the electronic preparation of mixed water offers a whole series of additional possibilities and increased operating comfort.
In its simplest form, the display is a three-digit display, whereby each alphanumerical is preferentially designed in the form of a seven-segment display. This display is substantially used for displaying the nominal and/or the actual temperatures.
Furthermore, in its simplest form, the operating unit comprises a menu key as well as two selector keys.
The capacity of the electronic device for preparing mixed water readily permits supplying one single device of this type with a great number of water outlets for mixed water prepared accordingly. The CPU of the device for preparing mixed water can be used in this connection for controlling the selected mixed water outlet in a targeted manner.
Furthermore, the problem of the invention is solved by a method for preparing mixed water.
The entire process for the preparation of mixed water can be carried out in this connection by means of only one single temperature sensor by conducting a gradient evaluation of the determined temperature curve in addition to a detection of only the actual temperature value. The curve of the temperature gradient makes it possible to determine whether through-flow of water is taking place or not.
The method as defined by the invention thus permits an acquisition of the through-flow without employing for this purpose a suitable through-flow sensor.
In an advantageous, further developed implementation of the method as defined by the invention, tracking of the setting element is switched off as soon and as long as the gradient of the temperature curve drops and is falling short of a threshold value that can be preset. In the concrete realization of the method, this means that the temperature is controlled only when through-flow of water is in fact taking place.
By switching off the setting element, which preferably is a stepping motor, any unnecessary consumption of water as well as any premature wear of the components installed under the plaster are avoided. The mechanically driven components of the control valve would otherwise be constantly moved even when no water is flowing through.
Finally, in connection with the method as defined by the invention, it is possible to distinguish between at least two temperature control ranges with different control accuracy. This makes it possible to provide for fine control within the normally useful range. This range can be provided with a controlling accuracy of, for example down to one tenth or half a degree. Such controlling accuracy is not required outside of the normal useful range. This range has to be detected only because the external ambient conditions have to be determined, in particular the ambient temperature. However, in order to change from this rough control range to the fine control range, it is not necessary to operate the system with final accuracy. Also this distinction between rough and fine control represents a measure for prolonging the useful life of the system because unnecessary movements of the setting element can be avoided in this way.
This feature can be developed further by preventing the setting element from tracking outside of a defined temperature range as well. This, too represents a measure that is implemented for avoiding unnecessary wear and consumption of energy.
In another, further developed embodiment, the method as defined by the invention is used for evaluating the gradient of the temperature curve for the purpose of detecting excess temperatures and/or failure of the cold water feed. The detection of any excess temperature represents an important safety feature in the sphere of the private household in order to prevent scalding of the user. The same aim is served if it is detected in due time whether the feed of cold water possibly may be interrupted. Any failure of the feed of cold water will otherwise in the first instant lead to a discharge of overheated water as well, which absolutely needs to be prevented for safety reasons.
A further feature of the efficiency of the method as defined by the invention lies in the fact that the controller unit is conceived as a controller equipped with the feature of self-parameterization. When the system is started up for the first time, at least one limit of the control range is reached, and a histogram is recorded during the further operation with the help of successfully controlled temperatures. The system is accordingly self-adjusting and, most of all, self-learning because the histograms are continuously processed and up-dated as the system is in operation, and, moreover, become increasingly more accurate as the operating duration of the system is increasing.
Furthermore, the storage element associated with the controller can be advantageously used in such a way that the aforementioned range of fine control can be defined without problems in different ways. For example, a distinction can be made between individual user profiles. For example, the temperature range to be used for small children is different from the one set for adults.
This can be taken into account by filing corresponding user profiles in the above-mentioned memory element.
In another advantageous embodiment of the invention, the controller is connected to an operating data acquisition device. It is possible in this way to realize additional features pertaining to comfort, like an operating hour counter or presetting time periods for the use of water in the hotel and restaurant trades.
Finally, fixed control programs can be programmed and called off as well, such as, or example a program for thermal disinfection, by which an extremely high temperature is controlled for a defined length of time. Such a program is very valuable, for example for thermal disinfection for killing legionellae.